Cortical Neurovascular Coupling Driven by Stimulation of Channelrhodopsin-2

Abstract

While functional imaging is widely used in studies of the brain, how well the hemodynamic signal represents the underlying neural activity is still unclear. And there is a debate on whether hemodynamic signal is more tightly related to synaptic activity or action potentials. This study intends to address these questions by examining neurovascular coupling driven by pyramidal cells in the motor cortex of rats. Pyramidal cells in the motor cortex of rats were selectively transduced with the light sensitive cation channel channelrhodopsin-2 (ChR2). Electrophysiological recordings and optical intrinsic signal imaging were performed simultaneously and synchronously to capture the neural activity and hemodynamics induced by optical stimulation of ChR2-expressing pyramidal cells. Our results indicate that both synaptic activity (local field potential, LFP) and action potentials (multi-unit activity, MUA) are tightly related to hemodynamic signals. While LFPs in γ band are better in predicting hemodynamic signals elicited by short stimuli, MUA has better predictions to hemodynamic signals elicited by long stimuli. Our results also indicate that strong nonlinearity exists in neurovascular coupling.

Effective Connectivity Measured Using Optogenetically Evoked Hemodynamic Signals Exhibits Topography Distinct from Resting State Functional Connectivity in the Mouse

“…Optogenetically evoked hemodynamic responses very closely resemble responses to peripheral stimulation ( Desai et al 2011 ; Kahn et al 2011 ; Scott and Murphy 2012 ; Vazquez et al 2014 ; Iordanova et al 2015 ), and sum in an approximately linear manner with measures of local neural activity ( Kahn et al 2011 ; Ji et al 2012 ). Further, both types of stimuli can elicit fast and slow components.…”

Noninvasive High-Speed Photoacoustic Tomography of Cerebral Hemodynamics in Awake-Moving Rats

“…48 Finally, wPAT can be used for preclinical studies by leaving animals in a conscious state. For example, it can be used to evaluate the effects of optogenetics 49,50 and to study stroke, and epilepsy as demonstrated in this work.…”

Patterned Optogenetic Modulation of Neurovascular and Metabolic Signals

“…[4][5][6][7][8] Such a spatial approach in the cortex would build upon previous temporal approaches for studying the hemodynamic response with optogenetics. Laser speckle contrast imaging, [9][10][11] intrinsic optical signal imaging, 9,12,13 and functional magnetic resonance imaging (fMRI) [14][15][16] have been combined with temporal optogenetic modulation to investigate cerebral hemodynamics.…”